GAYLE KING: The Justice Department has announced historic new regulations giving states the power to regulate marijuana use.

As Bill Whitaker reports, the new rules roll back 75 years of federal policy.

BILL WHITAKER: The Department will no longer prosecute, as long as states follow eight strict guidelines.

BRIAN VICENTE, "SENSIBLE COLORADO": Shop owners in Colorado and the medical marijuana patients, and even just marijuana consumers can really sleep a little easier tonight.

GOV. JAY INSLEE, (D), WASHINGTON (from press conference): I think that this is a very carefully calibrated and very common-sense approach by the federal government.

WHITAKER: The Justice Department is not giving states free rein. It's just loosening the reins a bit.

TOM ANGELL, "MARIJUANA MAJORITY": In 2009, they released a similar memo saying that they would respect state medical marijuana laws. But unfortunately, since that time, the Obama administration has overseen the closure of more state legal medical marijuana businesses than were closed during two terms of the Bush administration.

WHITAKER: Still, supporters of legalization say this could set the stage for more states to legalize marijuana.